A characterization of the data, including its intended use and limitations.

Abstract:

Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources within the same geographical areas. The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of patterns of biotic and abiotic phenomena, including geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another. A Roman numeral hierarchical scheme has been adopted for different levels for ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions (Commission for Environmental Cooperation Working Group, 1997). At Level III, the continental United States contains 105 regions whereas the conterminous United States has 85 (U.S. Environmental Protection Agency, 2011). Level IV ecoregions are further subdivisions of Level III ecoregions. Methods used to define the ecoregions are explained in Omernik (1995, 2004), Omernik and others (2000), and Gallant and others (1989).
Literature cited:
Commission for Environmental Cooperation Working Group, 1997, Ecological regions of North America- toward a common perspective: Montreal, Commission for Environmental Cooperation, 71 p.
Gallant, A. L., Whittier, T.R., Larsen, D.P., Omernik, J.M., and Hughes, R.M., 1989, Regionalization as a tool for managing environmental resources: Corvallis, Oregon, U.S. Environmental Protection Agency, EPA/600/3-89/060, 152p.
Omernik, J.M., 1995, Ecoregions - a framework for environmental management, in Davis, W.S. and Simon, T.P., eds., Biological assessment and criteria-tools for water resource planning and decision making: Boca Raton, Florida, Lewis Publishers, p.49-62.
Omernik, J.M., Chapman, S.S., Lillie, R.A., and Dumke, R.T., 2000, Ecoregions of Wisconsin: Transactions of the Wisconsin Academy of Science, Arts, and Letters, v. 88, p. 77-103.
Omernik, J.M., 2004, Perspectives on the nature and definitions of ecological regions: Environmental Management, v. 34, Supplement 1, p. s27-s38.
U.S. Environmental Protection Agency. 2011. Level III and IV ecoregions of the continental United States. U.S. EPA, National Health and Environmental Effects Research Laboratory, Corvallis, Oregon, Map scale 1:3,000,000. Available online at: http://www.epa.gov/wed/pages/ecoregions/level_iii_iv.htm.
Comments and questions regarding Ecoregions should be addressed to Glenn Griffith, USGS, c/o US EPA., 200 SW 35th Street, Corvallis, OR 97333, (541)-754-4465, email:griffith.glenn@epa.gov Alternate: James Omernik, USGS, c/o US EPA, 200 SW 35th Street, Corvallis, OR 97333, (541)-754-4458, email:omernik.james@epa.gov

Purpose:

Ecoregion maps assist managers of aquatic and terrestrial resources to understand the regional patterns of the realistically attainable quality of these resources

Supplemental information:

Electronic versions of ecoregion maps and posters as well as other ecoregion resources are available at: http://www.epa.gov/wed/pages/ecoregions.htm. Except for the Great Lakes, waterbodies were merged with surrounding ecoregion polygons, especially along coastlines. Ecoregions were digitized at 1:250,000 scale and are intended for large geographic extents (i.e. states, multiple counties, or river basins). Use for smaller areas, such as individual counties or a 1:24,000 scale map boundary, is not recommended.

Point Of Contact

Contact information for the individual or organization that is knowledgeable about the data.

Person: Marc Weber

Organization: U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory (NHEERL)

Position: GIS Analyst

Phone: (541) 754-4469

Email: weber.marc@epa.gov

Instructions:

http://www.epa.gov/nheerl/

Address type: mailing address

Address:

200 S.W. 35th Street

City: Corvallis

State or Province: OR

Postal code: 97333

Data Type

How the data are represented, formatted and maintained by the data producing organization.

The geographic areal domain of the data that describes the western, eastern, northern, and southern geographic limits of data coverage.

Bounding Coordinates

In Unprojected coordinates (geographic)

Boundary

Coordinate

West

-125.012651 (longitude)

East

-113.803595 (longitude)

North

43.455059 (latitude)

South

31.431829 (latitude)

+ Data Structure and Attribute Information

Overview

Summary of the information content of the data, including other references to complete descriptions of entity types, attributes, and attribute values for the data.

Entity and attribute overview:

Ecoregions are hierarchical, with Level IV being the most detailed and Level I defining the broadest classifications. Because of this hierarchy, Level IV features include appropriate codes and names for Levels III, II, and I. Likewise, Level III features contain Levels II and I, and Level II retains Level I information. Attributes pertaining to Level IV are only available for the Conterminous United States (US_). Level III has attributes for the US and North America (NA_) while Levels II and I apply to only North America. All features are identified by State and EPA Administrative Regions, as well. Fields ending with "KEY" combine ecoregion code and name attributes for convenient legends and are linked to style and layer files containing color definitions.

Entity and attribute detailed citation:

none

Direct spatial reference method: Vector

Attributes of ca_eco_l3.shp

Detailed descriptions of entity type, attributes, and attribute values for the data.

Description of point and vector spatial objects in the data using the Spatial Data Transfer Standards (SDTS) terminology.

Spatial data transfer standard (SDTS) terms

Feature class

Type: GT-polygon composed of chains

Count: 13

+ Data Quality and Accuracy Information

General

Information about the fidelity of relationships, data quality and accuracy tests, omissions, selection criteria, generalization, and definitions used to derive the data.

Logical consistency report:

Although ecoregion polygons and attributes have been checked for accuracy, some errors may remain. Polygons along state borders were reviewed and updated, May 2010. ARC/INFO software is used to create and maintain topological relationships.

Completeness report:

Unknown

Positional Accuracy

Accuracy of the positional aspects of the data.

Horizontal accuracy report:

Data were collected using methods that have unknown accuracy (EPA National Geospatial Data Policy [NGDP] Accuracy Tier 10). For more information, please see EPA's NGDP at http://epa.gov/geospatial/policies.html

+ Data Source and Process Information

Process Steps

Information about events, parameters, tolerances and techniques applied to construct or derive the data.

Process step information

Process Step 1

Process description:

1) U.S.G.S. 1:250,000 topographic maps are used to delineate the ecoregions. The lines drawn are manually digitized or scanned to produce georeferenced electronic files.

Process date: 2011

Process Step 2

Process description:

2) All base maps are joined together and errors along the edges are resolved.

Process date: 2011

Process Step 3

Process description:

3) Topology is established and the maps are reviewed for accuracy, completeness, and conformity with the original lines. Corrections are made as needed and topology regenerated.

Process date: 2011

Process Step 4

Process description:

4) Attributes are added.

Process date: 2011

Process Step 5

Process description:

5) Maps are plotted for visual inspection by two individuals and necessary changes made.

Process date: 2011

Process Step 6

Process description:

6) Ecoregions from all available states are merged and dissolved to identify and correct inconsistencies.

Process date: 2011

Process Step 7

Process description:

7) Polygons of the corrected seamless ecoregion features are extended beyond the coastal borders.

Process date: 2011

Process Step 8

Process description:

8) State and Ecoregion datasets are intersected.

Process date: 2011

Process Step 9

Process description:

9) Topology errors removed.

Process date: 2011

Process Step 10

Process description:

10) Final QA

Process date: 2011

Process Step 11

Process description:

11) Select State from national geodatabase

Process date: 2011

Process Step 12

Process description:

12) metadata

Process date: 2012

+ Data Distribution Information

General

Description of the data known by the party from whom the data may be obtained, liability of party distributing data, and technical capabilities required to use the data.

Resource description:

Downloadable Data

Distribution liability:

Although these data have been processed successfully on a computer system at the Environmental Protection Agency, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data to evaluate data set limitations, restrictions or intended use. The U.S. Environmental Protection Agency shall not be held liable for improper or incorrect use of the data described and/or contained herein.

Distribution Point of Contact

Contact information for the individual or organization distributing the data.

Organization: U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory (NHEERL)

Person: Marc Weber

Position: GIS Analyst

Phone: (541) 754-4469

Email: weber.marc@epa.gov

Instructions:

http://www.epa.gov/nheerl/

Address type: mailing address

Address:

200 S.W. 35th Street

City: Corvallis

State or Province: OR

Postal code: 97333

+ Metadata Reference

Metadata Date

Dates associated with creating, updating and reviewing the metadata.

Last updated: 20120426

Future metadata review date: 20160426

Metadata Point of Contact

Contact information for the individual or organization responsible for the metadata information.

Person: Marc Weber

Organization: U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory (NHEERL)

Position: GIS Analyst

Phone: (541) 754-4469

Email: weber.marc@epa.gov

Instructions:

http://www.epa.gov/nheerl/

Address type: mailing address

Address:

200 S.W. 35th Street

City: Corvallis

State or Province: OR

Postal code: 97333

Metadata Standards

Description of the metadata standard used to document the data and reference to any additional extended profiles to the standard used by the metadata producer.

Standard name: FGDC Content Standard for Digital Geospatial Metadata

Standard version: FGDC-STD-001-1998

Time convention: local time

FGDC Plus Metadata Stylesheet

Stylesheet: FGDC Plus Stylesheet

File name: FGDC Plus.xsl

Version: 2.3

Description: This metadata is displayed using the FGDC Plus Stylesheet, which is an XSL template that can be used with ArcGIS software to display metadata. It displays metadata elements defined in the Content Standard for Digital Geospatial Metadata (CSDGM) - aka FGDC Standard, the ESRI Profile of CSDGM, the Biological Data Profile of CSDGM, and the Shoreline Data Profile of CSDGM. CSDGM is the US Federal Metadata standard. The Federal Geographic Data Committee originally adopted the CSDGM in 1994 and revised it in 1998. According to Executive Order 12096 all Federal agencies are ordered to use this standard to document geospatial data created as of January, 1995. The standard is often referred to as the FGDC Metadata Standard and has been implemented beyond the federal level with State and local governments adopting the metadata standard as well.
The Biological Data Profile broadens the application of the CSDGM so that it is more easily applied to biological data that are not explicitly geographic (laboratory results, field notes, specimen collections, research reports) but can be associated with a geographic location. Includes taxonomical vocabulary. The Shoreline Data Profile addresses variability in the definition and mapping of shorelines by providing a standardized set of terms and data elements required to support metadata for shoreline and coastal data sets. The FGDC Plus Stylesheet includes the Dublin Core Metadata Element Set. It supports W3C DOM compatible browsers such as IE7, IE6, Netscape 7, and Mozilla Firefox. It is in the public domain and may be freely used, modified, and redistributed. It is provided "AS-IS" without warranty or technical support.

Instructions: On the top of the page, click on the title of the dataset to toggle opening and closing of all metadata content sections or click section links listed horizontally below the title to open individual sections. Click on a section name (e.g. Description) to open and close section content. Within a section, click on a item name (Status, Key Words, etc.) to open and close individual content items. By default, the Citation information within the Description section is always open for display.

Download: FGDC Plus Stylesheet is available from the ArcScripts downloads at www.esri.com.